<template>

    <div class="app-container">
  
      <h2 style="text-align: center;">发布新课程</h2>
  
      <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
        <el-step title="填写课程基本信息"/>
        <el-step title="创建课程大纲"/>
        <el-step title="最终发布"/>
      </el-steps>
  
      <el-form label-width="120px">
  
          <el-form-item label="课程标题">
              <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
          </el-form-item>
  
          <!-- 所属分类 TODO -->
          <el-form-item label="课程分类">
              <el-select
                  v-model="courseInfo.subjectParentId"
                  placeholder="一级分类" @change="subjectLevelOneChanged">
  
                  <el-option
                      v-for="subject in subjectOneList"
                      :key="subject.id"
                      :label="subject.title"
                      :value="subject.id"/>
  
              </el-select>
  
              <!-- 二级分类 -->
              <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
                  <el-option
                      v-for="subject in subjectTwoList"
                      :key="subject.id"
                      :label="subject.title"
                      :value="subject.id"/>
              </el-select>
          </el-form-item>
  
  
          <!-- 课程讲师 TODO -->
          <!-- 课程讲师 -->
          <el-form-item label="课程讲师">
          <el-select
              v-model="courseInfo.teacherId"
              placeholder="请选择">
  
              <el-option
                  v-for="teacher in teacherList"
                  :key="teacher.id"
                  :label="teacher.name"
                  :value="teacher.id"/>
  
          </el-select>
          </el-form-item>
  
          <el-form-item label="总课时">
              <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
          </el-form-item>
  
          <!-- 课程简介 TODO -->
        <!-- 课程简介-->
        <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>

  
  
          <!-- 课程封面 TODO -->
          <!-- 课程封面-->
          <el-form-item label="课程封面">
  
              <el-upload
                  :show-file-list="false"
                  :on-success="handleAvatarSuccess"
                  :before-upload="beforeAvatarUpload"
                  :action="BASE_API+'/eduoss/fileoss'"
                  class="avatar-uploader">
                  <img :src="courseInfo.cover">
              </el-upload>
  
          </el-form-item>
  
          <el-form-item label="课程价格">
              <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
          </el-form-item>
  
          <el-form-item>
              <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
          </el-form-item>
          </el-form>
    </div>
  </template>
<script>
import course from "@/api/teacher/course"
import subject from "@/api/teacher/subject"
import Tinymce from "@/components/Tinymce"
export default {
    components: { Tinymce },
    data() {
        return {
        courseInfo:{
            title: '',
            subjectId: '',//二级分类id
            subjectParentId:'',//一级分类id
            teacherId: '',
            lessonNum: 0,
            description: '',
            cover: '/static/01.jpg',
            price: 0
        },
        BASE_API: process.env.BASE_API, // 接口API地址
        saveBtnDisabled: false,
        teacherList: [],
        subjectOneList: [],
        subjectTwoList:[],
        courseId:'',
        }
    },
    
    created() { 
        if (this.$route.params && this.$route.params.id) {// 若有ID值则修改
            this.courseId = this.$route.params.id;
            this.getInfo();
        } else {
            // 若没有ID值则添加
            // 初始化所有讲师
            this.getListTeacher();
            // 初始化一级分类
            this.getOneSubject();
        }
        
    },

    methods: {
        // 根据课程ID查询信息
        getInfo() {
            course.getCourseInfoId(this.courseId)
                .then(response => { 
                    this.courseInfo = response.data.courseInfoVo;
                    // 查询所有分类，包含一级和二级
                    subject.getSubjectList()
                        .then(response => {
                            // 获取所有的一级分类
                            this.subjectOneList = response.data.list;
                            // 把所有的一级分类数组进行遍历，
                            for (var i = 0; i < this.subjectOneList.length; i ++ ) {
                                // 获取每个一级分类
                                var oneSubject = this.subjectOneList[i];
                                //比较当前courseInfo里面一级分类id和所有的一级分类id是否一样
                                if (this.courseInfo.subjectParentId === oneSubject.id) {
                                    // 获取一级分类中的所有二级分类
                                    this.subjectTwoList = oneSubject.children;
                                }
                            }
                        })

                        // 初始化所有讲师
                        this.getListTeacher();
                })
        },
        // 上传成功调用
        handleAvatarSuccess(res, file) {
            this.courseInfo.cover = res.data.url;
        },

        // 上传之前调用
        beforeAvatarUpload(file) {
            const isJPG = file.type === 'image/jpeg'
            const isLt2M = file.size / 1024 / 1024 < 2

            if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
            }
            if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
            }
            return isJPG && isLt2M
        },
        subjectLevelOneChanged(value) {
            // value为一级分类id
            for (var i = 0; i < this.subjectOneList.length; i ++ ) {
                var oneSubject = this.subjectOneList[i]; 
                // 判断所有一级分类ID和点击一级分类ID是否一样
                if (oneSubject.id === value) {
                    this.subjectTwoList = oneSubject.children;
                    this.courseInfo.subjectId = '';
                } 
            }

        },
        getOneSubject() {
            subject.getSubjectList()
                .then(response => {
                    this.subjectOneList = response.data.list;
                })
        },
        getListTeacher() {
            course.getListTeacher()
                .then(response => {
                    this.teacherList = response.data.teacher;
                })
        },
        addCourse() {
            course.addCourseInfo(this.courseInfo)
                .then(response => {
                    this.$message({
                        type: "success",
                        message: "添加课程信息成功"
                    })
                    this.$router.push({path:'/course/chapter/' + response.data.courseId})
                })
        },
        updateCourse() {
            course.updateCourseInfo(this.courseInfo)
                .then(response => {
                    this.$message({
                        type: "success",
                        message: "修改课程信息成功",
                    })
                    this.$router.push({path:'/course/chapter/' + this.courseId})
                })
        },
        saveOrUpdate() {
            // 判断是添加还是修改
            if (!this.courseInfo.id) {
                this.addCourse();
            } else {
                this.updateCourse();
            }
        }
    },
}
</script>

<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>